The primary approach to the prevention of radiation proctitis is the use of contemporary conformal radiation therapy techniques (e.g. intensity-modulated radiation therapy, image-guided radiation therapy) that minimise the dose of radiation to the rectum while maximising the dose to the tumour.
Attempts to use adjunctive medical therapy (e.g. amifostine) to prevent the development of radiation proctitis has shown some benefit in small trials in reducing symptoms of both acute and chronic radiation proctitis.rr Rectal administration has also been trialledr and it is recommended by MASCC/ISOO for the prevention of radiation proctitis,r although it is not widely used in clinical practice.
Sucralfate has also been evaluated for prophylaxis against acute radiation injury.r However, placebo-controlled phase III trials have detected no benefit from either topical or oral sucralfate.rr
As well as the newer radiation delivery methods, other physical techniques have been used to minimise the dose of radiation reaching normal tissues. For example, attempts to protect the rectum during radiotherapy for prostate cancer have included placing the patient in a supine position, transperineal injection of collagen between the prostate and rectum, and prostate immobilisation using endorectal balloons.r
A number of dietary interventions have been trialled in patients receiving pelvic irradiation in an attempt to either prevent or control gastrointestinal symptoms. Such symptoms may result from radiation proctitis but also from more proximal bowel damage. Interventions have included lactose restriction, fat restriction or modification and fibre supplementation. Although no specific treatments have been recommended, there is some evidence that dietary modification may reduce acute symptoms of diarrhoea in patients receiving pelvic irradiation.r
In the absence of comprehensive management guidelines, a range of treatment options have been explored. These are aimed at minimising the risk of injury to the rectum during radiation therapy, providing supportive treatment for patients with acute radiation proctitis, and symptom-based management of those with chronic radiation proctitis.
Treatment of established radiation proctitis is generally classified as being medical, endoscopic or surgical, but the evidence for many therapies is limited and more large-scale, prospective trials are required to evaluate their benefit.r
A range of medical treatments have been used to manage radiation proctitis. Some of these are supportive measures and include rehydration therapy, stool softeners, oral and topical analgesics and antispasmodics.
Although there are no definitive guidelines currently available for the management of radiation proctitis, a number of recommendations are included in clinical practice guidelines developed by The Mucositis Guidelines Leadership Group of the Multinational Association of Supportive Care in Cancer and International Society of Oral Oncology-MASCC/ISOO)r as per table 3 below.
Table 3. adapted from MASCC/ISOO clinical practice guidelines for gastrointestinal mucositis
|MASCC/ISOO recommendations relevant to the management of radiation proctitis (MASCC/ISOO evidence levels)
|Recommendations for treatment (i.e. strong evidence supports effectiveness in the treatment setting listed)
- the panel recommends that intravenous amifostine be used, at a dose of greater than or equal to 340 mg/m2 to prevent radiation proctitis in patients receiving radiation therapy (II)
|Suggestions for treatment (i.e. weaker evidence supports effectiveness in the treatment setting listed)
- the panel suggests that sucralfate enemas be used to treat chronic radiation-induced proctitis in patients with rectal bleeding (III)
- the panel suggests that hyperbaric oxygen be used to treat radiation-induced proctitis in patients receiving radiation therapy for a solid tumour (IV)
|Recommendations against treatment (i.e. strong evidence indicates lack of effectiveness in the treatment setting listed)
(Note: this therapy is expensive and not readily available. This treatment may be best reserved for challenging cases)
- the panel recommends that misoprostol suppositories not be used to prevent acute radiation-induced proctitis in patients receiving radiation therapy for prostate cancer (I)
Several other therapies have been evaluated in patients with radiation proctitis, including sodium butyrate, metronidazole, formalin however there is limited evidence to support their use.r Many authors point out that large, prospective, randomised, controlled trials are needed to critically evaluate the available options.rrr
Endoscopic treatments: There are a variety of endoscopic approaches which may assist in the management of chronic radiation proctitis designed to control bleeding. The most common of these is Argon plasma coagulation (APC) due to cost effectiveness, positive results and the ability to treat large areas.
Surgery may be considered for patients with chronic radiation proctitis where conservative treatments have been unsuccessful.
Patients should be referred to a gastrointestinal specialist to explore options where appropriate in conjunction with the treating radiation oncologist.
Patients with severe symptoms of acute radiation proctitis may need to have their radiation therapy suspended for a short period.r Otherwise, treatment is of a supportive nature including:
- maintaining adequate hydration
- dietary changes (see above)
- antidiarrhoeals as required
- analgesics if pain is a problem
- antispasmodics for tenesmus
- topical analgesia for anal soreness
- oral/rectal steroids and/or butyrate enemas may be considered.
Chronic radiation proctitis can present with a range of symptoms and these will largely determine the choice of management strategy. The level of intervention required will depend on the severity of symptoms and the risk-benefit profile of available treatment options.
Because of uncertainty about the natural history of chronic radiation proctitis, the limited evidence for many therapies and the risk of adverse effects, a conservative management approach is advocated by some authors.rrr This would include supportive measures similar to those used in acute proctitis. In addition, patients with rectal bleeding who are taking aspirin or warfarin should have their need for these medications reviewed.r Consideration should also be given to other factors which may be contributing to symptoms including more proximal gastrointestinal damage producing gastrointestinal hurry.r Additional treatments would be considered on the basis of the evidence available for their use and the likely risk of adverse effects, as outlined above.